CAL B737 Very, Very Long Takeoff Roll / MD80 Stall Recovery
 

One of the recent threads where timing V-speeds has been discussed was that of a China Airlines 737, which took all of the runway, and then a bit, and only just got airborne: Cracked CAL 737 only just gets airborne

What made that one even more confusing was that it was an empty test/transfer flight after significant structural repairs.

Probably not of direct relevance here, since indications are that they did not use up excess runway.

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Stall recovery?

The consensus seems to be that the stall recovery procedure calls for "Max thrust, flaps 15°"

However, in the (admittedly not very recent) FM that I have seen it says for stall recovery at low altitudes merely to call and set "MAX THROTTLES", which means firewalling the throttles to the forward stop, and levelling the wings if in a turn. It specifically mentions that:

I'm just curious about the flaps setting, and when or if, and why the procedure might have changed.


Regards,
Bernd

Just my thoughts,

Wouldn't a partially deployed or recycling thrust reverser (on one side only) explain the extra 500 meters of runway used before lifting off? If that is a plausible scenario, why was there no reverser light or warning indication on the flight deck? Apparently the crew had no notion of anything wrong with the aircraft during the take-off roll.

And could the "bang" heard by some survivors have been the reverser extending to fully deployed position just after lift-off?


Green-dot

The supposed CVR data showed on Argentina TV is just a FAKE, nothing real. Not reliable at all. This info is now confirmed.

ZQA297/30 a big bow and thank you :D
Finally a post that puts some value back to the reading of tons of crap on this supposed "Professional Pilot" site.

It proves once more that no checklist nor warning system will protect you to no end...

I applaud and share with your It is a good (and comfy for pax) way of letting the lift and energy built up. Many a MTOW what is the wind doing or not too sure if wings clean TO will benefit from this technique. Unfortunately there are still many pilots yanking the craft in the element iso of the gentle pull necessary to aviate...


live 2 fly 2 live

In the 1978 Cranbrook B-737 accident, the accident report mentioned as one of the causes that the uncommanded reverser deployment caused the throttle to come back to idle so quickly it broke the thumb of the pilot with his hands on the throttle at the time -- the distraction from the resulting pain was cited as a contributing factor.

So if an uncommanded reverser deployment before coming back to ground happened on this flight, how hard would the throttle come back on this different type?

We are looking at possibilities of insufficient thrust combined with insufficient flaps/slats, and/or reverser deployment. Ockham's Razor of course argues against fancy combinations, but transport accidents are usually a result of lining up holes in the cheese.

Next question: How many pilots have tried out a flapless takeoff in the sim? I know the Viscount would never lift off, but that's all I can contribute.

The earlier debate about the value of having the runways and general airport area monitored by cameras was deflected by news that the investigators were studying video of the crash. Can anyone enlighten us whether what we are talking about is:

a) amateur or plane spotter video,
b) CCTV cameras designed for passenger or road traffic surveillance that “caught” the crash by accident, or
c) Cameras installed by the airport specifically to monitor take-offs and landings for safety or flight operations performance that we haven't yet been told about.

Ockham's Razor...I don't think ockham flew a jet...finding an easy answer doesn't mean its the right answer.

gentle rotations...I would like to think that long ago we learned that a gentle rotation is vital...especially with icing conditions.

someone mentioned the CVR transcript is now a phony...if so, will someone please verify!

as to thrust reverser deployment, the engine should go to idle, you attempt to stow and if unable you shut down the engine...BUT DURING EVERY EMERGENCY, YOU FLY THE PLANE FIRST.

I noticed that someone was talking about a "takeoff stall" recovery and said the call was "MAX THRUST"...we say "FIREWALL POWER" and or FIREWALL THRUST...SELECTING FLAPS 15...but if you already have flaps 15, that is just a confirmation . There is a difference between max and firewall in our lexicon.

It would seem to me that if the CVR was recovered an initial playback should have recorded a stall warning, or a fire bell. And if neither were present, we have something really odd.

"How many pilots have tried out a flapless takeoff in the sim?"

And I would like to add the same question concerning uncommanded reverse.

My experience on the sim on this (corporate jet, though) is restricted to a deployment on ground, well before V1. Even knowing what´s going to happen, it´s quite a task. I could imagine that they would have had a hard time if the reverse popped open during or shortly after rotation.

avionero:

the first time in the sim for this type, without any briefing, the thrust reverser deployed just after takeoff. our sim instructor said, without looking at any checklist, what makes sense to try to fix this?

so we tried to stow the reverser...unable
and then we cut the fuel to the engine

and then we flew around the pattern and landed like we would on one engine, because we were now on one engine.

Remember a thrust reverser does not reverse 100 percent of thrust...perhaps 60 percent at max thrust is reversed...and at idle, its not too bad.

It's in Spanish, but I found a forum thread from a person that saw the accident from ground:

Foros de AviationCorner.net - Testigo en directo de accidente de MD Spanair

"Lo 1º quiero expresar mis condolencias a todos los familiares de la tripulación como del pasaje. Descansen en paz.
Estaba en rampa de la T-4s, eran aproximadamente las 14:25, vi como despegaban un md de Spanair y me llamo la atención que utilizó mucha distancia para despegar casi igual que la que utilizan los A-340.
Levantó casi a el final de pista y se ladeaba hacia la izquierda luego se giró hacia derechas y el ala tocó el suelo, a continuación el avión se arrastró 500m se metio en una arboleda y explotó provocando una bola dem fuego grandisíma.
En ese mismo momento me temblaban las piernas por lo que habia visto, no daba credito, fue espeluznante el pensar que el avión estaria repleto de pasaje.
Espero que mis ojos no vuelvan a ver una cosa semejante.
Siento asco por lo que esta saliendo en los periodicos, no logro como pueden publicar que un piloto puede volar si su avión no esta enb condiciones; poniendose peligro su vida y la todo el pasaje.
Estos comentarios envenenan a los familiares de las victimas.
Soy nuevo en la web y lamento que mi primer comentario sea por una castrofe en un aeropuerto español.
Un saludo a todos.
DESCANSEN EN PAZ"

Like a pulled C/B you mean?

I haven't done a flapless TO in the SIM, but did do a few deployed reversers. The first being in my initial. Let me tell you. Close to the ground it is hell to get out of. You will get an uncommanded yaw like you have never seen. It is almost to the point of saying that this scenario is one instance where priorities change. Memory items, aviate, navigate :sad:.
It is imperative to remedy that situation. 100% thrust on one side and -60% on the other absolutely kills you. However an unlocked reverser that close to the ground should have been seen by the investigators on the video. If the engine does not surge you will see two huge shiny slabs on one side and in many cases soot shooting from the reverser buckets upwards and downwards. I think the reverser was a last ditch attempt to stop the plane...........ASAP.

Eyewitness accounts of the aircraft's excessive takeoff run and difficulty getting airborne are easily explained and its not power.
-aircraft was heavy
-hot high airport
-tailwind
-improved climb speed-take less flap to improve climb grad-reduced thrust/flex and improved climb shouldnt go together btw-

Now thats for a normal situation,an aircraft that is properly configured.It will use more of the runway to achieve a higher V2 speed and better climb gradient.But once it reaches Vr,it will rotate and lift off at 6-8 deg body angle(MD-80) and climb away normally.For an aircraft that has no flaps/slats extended,it will rotate until 11 degreees body angle,struggle into the air,and if the stall recovery procedure is not flown,it will stall on leaving ground effect.On this aircraft,the stick pusher/autoslats would not have been active because the slats were retracted.Also,it is quite possible that a flex takeoff was performed although this is naughty.Some operators deliberately use opt flap to improve engine life(actually youre supposed to use it when you're climb limited)..ie..take very low flap,still reduce thrust by about 20% and end up having ridiculously high Vr and unnecesssary RTO risks.It should be done with full TO thrust.

Could some Mad Dog pilot please be kind enough to say what signs you might get when this bird is stuck in air mode whilst on the ground?Anything you can think of like parking brake/antiskid/autobrake anomalies..so far the reports indicate that the pilots mentioned only this probe heater to the engineer which sevenstrokeroll has already confirmed is heated whilst airborne but not on ground.They would have armed the autobrake in the T.O position as part of pre-flight.If the aircraft was in the air mode,presumably a disarm light would have alerted them and this may have been mentioned to the engineer as well.

Translation of Spanish post above (to the best of my ability):


First I would like to express my condolences to all the families of the crew and pasengers. Rest in peace.

I was in ramp of the T-4s, at approximately 14:25, I saw how a Spanair MD took off and it caught my attention that it used a long distance to take off, almost equal to what the A-340 uses.

It lifted off almost at the end of the runway and was rolling to the left when it turned to the right and the wing touched the ground, after which the aeroplane dragged itself 500m, hit a grove of trees and exploded in a huge ball of flame.

At that moment my legs shook over what I had seen,(no daba credito) ,the thought that the plane was full of passengers was horrifying. I hope that my eyes never see anything like it again.

I feel disgusted about what is appearing in the newspapers - how can they publish that a pilot could fly if his plane was not in condition? putting his life and that of all the passengers in danger.

These comments embitter the families of the victims.

I am new in the web and i am sorry that my first comment is about a catastrophe at a Spanish airport.

My salutations to everyone.

I think the MD80 is one of the planes with the most amount of differering options out there. There's EFIS, non-EFIS, autobrakes or not, FMC's or not, switch locations on the overhead, TOW options etc etc. I have flown 4 MD-82's and one MD-83. 2 82's were the sisterships. One had a higher TO weight of 67.8 tons, but the units were in pounds. None had GPS-FMC's. The 4th -82 has the same TO weight of 67.8, but weights in kilo's and some switch positions wre different. The MD-83 is a HGW version which at one time was supposed to be delivered to the US military if memory serves me correct. Than planned didn't go through and there are a few out there. The have a TO weight of 72.6 tons and a MLW of 68.0 tons. That's 9 tons of extran landing weight than an -82. 5tons more than a normal -83.

The reason I say is that this plane may not have had an autobrake system. On the MD-82, the most prominent item being the RAT probe. It is the most obvious. Other than that, the cabin blower fans under the front cabin floor will stop operating. But only a lot of experience and a relaxed keen ear can detect that. If it was night time, you can also see the strobe lights flashing away on the wing tips. Other than that even though there's quite a list of inputs few may be aparent to crews. Remember also that the ground shift system abviously has a mechanical part and hydraulic part. It may be that for example that the landing gear anti retract knob which should retract when airborne, or the rudder controlled nosewheel steering which should be disconnected if the plane is in air mode, do operate as it should because electrecally the plane would thinks it's in the air, but mechanically (because the nose strut is still compressed) it is in gournd mode. I think these two systems are affected mechanically.

EDIT: If the taxi out checklist was carried out you would also have noticed that when carrying out the flight control check, the SPOILER DEPLOYED caution light fails to illuminate. In the check you verify that the light illuminates to confirm if your flight controls behave as they should. So if the checklist was carried out they should have noticed it.

Xander

rananim

there is a button near the gear handle that is sticking out about an inch...press it and you override the ground shift mechanism and you can retract the gear on the ground

thinking it was in the air, this button would be flush with the instrument panel.

xantham above is quite right...we just don't know the exact configuration of this plane. indeed, former TWA ships had switches moving opposite direction to american airlines ships.

the RAT thing is really weird, you just don't see EPR settings that WRONG unless the plane is heating the RAT...and the only way it heats the RAT is when it thinks its airborne.

Now that the CVR thing is a phony, I stand by my theory

skid marks photo
 

Look at this photo of the skid marks in the grass to the right of rwy 36L. Not being published before

Informativos Telecinco.com - Imgenes exclusivas de la tragedia - Galería de fotos

(sorry don't know how to put the image on the forum, is picture 1 of the gallery, if anyone can help on this please do so)

JM

"Wouldn't a partially deployed or recycling thrust reverser (on one side only) explain the extra 500 meters of runway used before lifting off? If that is a plausible scenario, why was there no reverser light or warning indication on the flight deck? Apparently the crew had no notion of anything wrong with the aircraft during the take-off roll."


i am no professional pilot but:
if the right reverser would have deployed during take off run don't you think the crew would have realized that the plane drifts extremely to the right ?

I think the thing that would get my attention if the reverser deployed would be the light that says reverser unlocked and rev ready

they are in front of your face, and if you can see the airspeed or horizon you would see these

the stall warning is a huge sign saying "stall", a profound HORN and a stick shaker, though no pusher. it can scare the hell out of you.

does anyone know if the plane pushed back or did a power back (reversed)?

Spanish media speculates with the investigation concentrating in just about anything. Let's assume the plane stalled soon after leaving the ground, as the video tape and witnesses account seem to indicate.

Depending on what press you read/watch, even as today, still each claims the investigation is concentrating on one of different scenarios (pick your choice):

-Sudden engine failure. But there is no hard evidence on noises, fires, recovery procedures failing (full thrust on the other engine, etc), reliable witnesses, etc, prior to the airplane hitting the ground. Of course, it could've still happened and could be a likely cause, but shouldn't have been enough of a single cause to stall so early on and pilots not be able to recover. Also, doesn't quite fit the picture of the reportly somewhat long taxiing, etc.

-Others, on engine "lacking thrust". But surely crew felt it all seemed good enough to reach V1 and trusted it was enough to become airborne. Compressor(s) may have stalled etc, but likelihood of both engines failing to produce V2m after V1 w/o pilots being to do anything about it and no "loud" (i.e. explosion, etc) signs while still deciding to try to become airborne ...

-Others yet, on assymetrical reverser deployment. But the airplane showed no signs of difficult yaw/roll while on-ground, only shortly after it became airborne at enough height to roll both, to the left and to the right according to witnesses/survivors (pilot could probably over-recover, but still kind of unlikely) before the wing hitting the ground. Reverser seemed fully and properly deployed in at least one engine, but nobody has authoratively stated (some have, but never mentioned sources) that the second reverser was or was not deployed.

Still, having one or both reversers getting accidentally fully deployed, apparently after V1 but before V2, is a long strech. But it could've happened, of course.

Nonetheless, chances are that, once it became clear they were gonna crash, pilots probably tried to deploy them, but perhaps damage to the plane at that point or other factors (such as pilots being already injured from the first/second/third "fall" while bouncing around up to 6 times during about 500m before final explosion) made fully deploying succesfully only one of the reversers possible.

-Very few media is emphasising flaps/slats mistake or malfunction or speed/thrust gross miscalculations, coupled with alarms performance malfunction (i.e. plane thinking it was in air mode due to other sensors malfunction) or alarms de-activation (from earlier aborted T/O and/or repairs).

The likehood of this, I'll leave to each one of you to decide. How this could've happened w/o the pilots noticing on time, or the alarms failing to warn on time, or the pilots being unable to recover from stall on time, I'll also leave to each one of you to decide.

Let's remember this was likely a plane loaded on the heavy side, on lowish-density air and that it possibly did take some extra (grossly estimated) 500m than usual to become airborne and that it reportly hardly left ground-effect area with two (let's assume properly working) engines. There is some vague reporting on nearby witnesses thinking the "angle" of attack during roll was also "unusual" (i.e. either too steep or too shallow).

Many other scenarios are, of course, possible (sudden cargo imbalance, etc) or could've helped with the accident, but there is little hard evidence on just about anything other than the plane rolled and fell shortly after a T/O maneuver that looked to several witnesses (on video or survivors or external witnesses) like didn't have enough "power" to be completed successfully with no other apparent (visible or audible from the outside or the PAX inside) warnings.